Early onset cerebellar ataxia with retained tendon reflexes is distinctive clinical syndrome characterized by progressive cerebellar ataxia of unknown etiology with an onset within the first two decades. This disorder was distinguished from Friedreich's ataxia by the preservation of the deep tendon reflexes. There is 22-year-old male with 13 year history of slowly progressive cerebellar ataxia and dysarthria. His elder brother, also, has milder clinical manifestations, electrophysiological and radiological abnormalities. We experienced two cases of early onset cerebellar ataxia with retained tendon reflexes developed in brothers which was diagnosed by clinical manifestations, electrophysiologic, radiologic studies and report with brief review of related literatures.